Photoreal character configurations for spatial computing

ABSTRACT

Systems and methods for displaying a virtual character in a mixed reality environment are disclosed. In some embodiments, a view of the virtual character is based on an animation rig comprising primary joints and helper joints. The animation rig may be in a pose defined by spatial relationships between the primary joints and helper joints. The virtual character may be moving in the mixed reality environment. In some instances, the virtual character may be moving based on a comparison of interestingness values associated with elements in the mixed reality environment. The spatial relationship transformation associated with the movement may be indicated by movement information. In some embodiments, the movement information is received from a neural network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Patent ApplicationNo. 62/858,251, filed Jun. 6, 2019, the contents of which isincorporated herein by reference in its entirety.

FIELD OF INVENTION

This disclosure is generally related to systems, methods, andconfigurations pertaining to portrayal and interaction associated withobjects in a mixed reality environment.

BACKGROUND

There have been improvements in virtual character technology on screen,in film, and in gaming. Next steps in the development of virtualcharacters may be improvements virtual character actions andinteractions to give them attributes that are more believable to aviewer and giving the viewer and more immersive experience. Virtualcharacters who are more aware of and can interact more directly withusers in a virtual, augmented reality, or mixed reality environment mayprovide the user a more compelling experience.

However, presenting the virtual characters in a more life-like mannermay require more processing. Optimizing the presentation of morelike-life virtual characters may be especially important for a mixedreality system, which may have hardware limitations such as finitebattery capacity and finite amount of processing resource to maintainthe system's portability. Optimization of virtual character presentationin a mixed reality environment includes meeting a high bar of creating aconvincing virtual character—rendering, animation, deformations,clothing, hair, and behavior may need to meet a certain intangiblequality level for the character to be believable while also fittingwithin the performance envelope of the mixed reality system hardware.

BRIEF SUMMARY

Systems and methods for displaying a virtual character in a mixedreality environment are disclosed. In some embodiments, a view of thevirtual character is based on an animation rig comprising primary jointsand helper joints. The animation rig may be in a pose defined by spatialrelationships between the primary joints and helper joints. Thelocations of helper joints may be determined by a helper joint placementcriterion. The virtual character may be moving in the mixed realityenvironment. In some instances, the virtual character may be movingbased on a comparison of interestingness values associated with elementsin the mixed reality environment. The spatial relationshiptransformation associated with the movement may be indicated by movementinformation. In some embodiments, the movement information is receivedfrom a neural network. In some embodiments, the movement information isdetermined using a regression analysis.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C illustrate exemplary environments, according to one or moreembodiments of the disclosure.

FIGS. 2A-2D illustrate components of exemplary mixed reality systems,according to embodiments of the disclosure.

FIG. 3A illustrates an exemplary mixed reality handheld controller,according to embodiments of the disclosure.

FIG. 3B illustrates an exemplary auxiliary unit, according toembodiments of the disclosure.

FIG. 4 illustrates an exemplary functional block diagram of an exemplarymixed reality system, according to embodiments of the disclosure.

FIG. 5 illustrates an exemplary character in a mixed realityenvironment, according to embodiments of the disclosure.

FIG. 6 illustrates an exemplary animation rig in a mixed reality system,according to embodiments of the disclosure.

FIGS. 7A-7B illustrate aspects of an exemplary mixed realityenvironment, according to embodiments of the disclosure.

FIG. 8 illustrates an exemplary method of a mixed reality system,according to embodiments of the disclosure.

FIG. 9 illustrates an exemplary method of a mixed reality system,according to embodiments of the disclosure.

DETAILED DESCRIPTION

In the following description of examples, reference is made to theaccompanying drawings which form a part hereof, and in which it is shownby way of illustration specific examples that can be practiced. It is tobe understood that other examples can be used and structural changes canbe made without departing from the scope of the disclosed examples.

Like all people, a user of a mixed reality system exists in a realenvironment—that is, a three-dimensional portion of the “real world,”and all of its contents, that are perceptible by the user. For example,a user perceives a real environment using one's ordinary humansenses—sight, sound, touch, taste, smell—and interacts with the realenvironment by moving one's own body in the real environment. Locationsin a real environment can be described as coordinates in a coordinatespace; for example, a coordinate can comprise latitude, longitude, andelevation with respect to sea level; distances in three orthogonaldimensions from a reference point; or other suitable values. Likewise, avector can describe a quantity having a direction and a magnitude in thecoordinate space.

A computing device can maintain, for example in a memory associated withthe device, a representation of a virtual environment. As used herein, avirtual environment is a computational representation of athree-dimensional space. A virtual environment can includerepresentations of any object, action, signal, parameter, coordinate,vector, or other characteristic associated with that space. In someexamples, circuitry (e.g., a processor) of a computing device canmaintain and update a state of a virtual environment; that is, aprocessor can determine at a first time to, based on data associatedwith the virtual environment and/or input provided by a user, a state ofthe virtual environment at a second time t1. For instance, if an objectin the virtual environment is located at a first coordinate at time t0,and has certain programmed physical parameters (e.g., mass, coefficientof friction); and an input received from user indicates that a forceshould be applied to the object in a direction vector; the processor canapply laws of kinematics to determine a location of the object at timet1 using basic mechanics. The processor can use any suitable informationknown about the virtual environment, and/or any suitable input, todetermine a state of the virtual environment at a time t1. Inmaintaining and updating a state of a virtual environment, the processorcan execute any suitable software, including software relating to thecreation and deletion of virtual objects in the virtual environment;software (e.g., scripts) for defining behavior of virtual objects orcharacters in the virtual environment; software for defining thebehavior of signals (e.g., audio signals) in the virtual environment;software for creating and updating parameters associated with thevirtual environment; software for generating audio signals in thevirtual environment; software for handling input and output; softwarefor implementing network operations; software for applying asset data(e.g., animation data to move a virtual object over time); or many otherpossibilities.

Output devices, such as a display or a speaker, can present any or allaspects of a virtual environment to a user. For example, a virtualenvironment may include virtual objects (which may includerepresentations of inanimate objects; people; animals; lights; etc.)that may be presented to a user. A processor can determine a view of thevirtual environment (for example, corresponding to a “camera” with anorigin coordinate, a view axis, and a frustum); and render, to adisplay, a viewable scene of the virtual environment corresponding tothat view. Any suitable rendering technology may be used for thispurpose. In some examples, the viewable scene may include some virtualobjects in the virtual environment, and exclude certain other virtualobjects. Similarly, a virtual environment may include audio aspects thatmay be presented to a user as one or more audio signals. For instance, avirtual object in the virtual environment may generate a soundoriginating from a location coordinate of the object (e.g., a virtualcharacter may speak or cause a sound effect); or the virtual environmentmay be associated with musical cues or ambient sounds that may or maynot be associated with a particular location. A processor can determinean audio signal corresponding to a “listener” coordinate—for instance,an audio signal corresponding to a composite of sounds in the virtualenvironment, and mixed and processed to simulate an audio signal thatwould be heard by a listener at the listener coordinate—and present theaudio signal to a user via one or more speakers.

Because a virtual environment exists as a computational structure, auser may not directly perceive a virtual environment using one'sordinary senses. Instead, a user can perceive a virtual environmentindirectly, as presented to the user, for example by a display,speakers, haptic output devices, etc. Similarly, a user may not directlytouch, manipulate, or otherwise interact with a virtual environment; butcan provide input data, via input devices or sensors, to a processorthat can use the device or sensor data to update the virtualenvironment. For example, a camera sensor can provide optical dataindicating that a user is trying to move an object in a virtualenvironment, and a processor can use that data to cause the object torespond accordingly in the virtual environment.

A mixed reality system can present to the user, for example using atransmissive display and/or one or more speakers (which may, forexample, be incorporated into a wearable head device), a mixed realityenvironment (“MRE”) that combines aspects of a real environment and avirtual environment. In some embodiments, the one or more speakers maybe external to the wearable head device. As used herein, a MRE is asimultaneous representation of a real environment and a correspondingvirtual environment. In some examples, the corresponding real andvirtual environments share a single coordinate space; in some examples,a real coordinate space and a corresponding virtual coordinate space arerelated to each other by a transformation matrix (or other suitablerepresentation). Accordingly, a single coordinate (along with, in someexamples, a transformation matrix) can define a first location in thereal environment, and also a second, corresponding, location in thevirtual environment; and vice versa.

In a MRE, a virtual object (e.g., in a virtual environment associatedwith the MRE) can correspond to a real object (e.g., in a realenvironment associated with the MRE). For instance, if the realenvironment of a MRE comprises a real lamp post (a real object) at alocation coordinate, the virtual environment of the MRE may comprise avirtual lamp post (a virtual object) at a corresponding locationcoordinate. As used herein, the real object in combination with itscorresponding virtual object together constitute a “mixed realityobject.” It is not necessary for a virtual object to perfectly match oralign with a corresponding real object. In some examples, a virtualobject can be a simplified version of a corresponding real object. Forinstance, if a real environment includes a real lamp post, acorresponding virtual object may comprise a cylinder of roughly the sameheight and radius as the real lamp post (reflecting that lamp posts maybe roughly cylindrical in shape). Simplifying virtual objects in thismanner can allow computational efficiencies, and can simplifycalculations to be performed on such virtual objects. Further, in someexamples of a MRE, not all real objects in a real environment may beassociated with a corresponding virtual object. Likewise, in someexamples of a MRE, not all virtual objects in a virtual environment maybe associated with a corresponding real object. That is, some virtualobjects may solely in a virtual environment of a MRE, without anyreal-world counterpart.

In some examples, virtual objects may have characteristics that differ,sometimes drastically, from those of corresponding real objects. Forinstance, while a real environment in a MRE may comprise a green,two-armed cactus—a prickly inanimate object—a corresponding virtualobject in the MRE may have the characteristics of a green, two-armedvirtual character with human facial features and a surly demeanor. Inthis example, the virtual object resembles its corresponding real objectin certain characteristics (color, number of arms); but differs from thereal object in other characteristics (facial features, personality). Inthis way, virtual objects have the potential to represent real objectsin a creative, abstract, exaggerated, or fanciful manner; or to impartbehaviors (e.g., human personalities) to otherwise inanimate realobjects. In some examples, virtual objects may be purely fancifulcreations with no real-world counterpart (e.g., a virtual monster in avirtual environment, perhaps at a location corresponding to an emptyspace in a real environment).

In some examples, virtual objects hay have characteristics that resemblecorresponding real objects. For instance, a virtual character may bepresented in a virtual or mixed reality environment as a life-likefigure to provide a user an immersive mixed reality experience. Withvirtual characters having life-like characteristics, the user may feellike he or she is interacting with a real person. In such instances, itis desirable for actions such as muscle movements and gaze of thevirtual character to appear natural. For example, movements of thevirtual character should be similar to its corresponding real object(e.g., a virtual human should walk or move its arm like a real human).As another example, the gestures and positioning of the virtual humanshould appear natural, and the virtual human can initial interactionswith the user (e.g., the virtual human can lead a collaborativeexperience with the user). Presentation of virtual characters havinglife-like characteristics is described in more detail herein.

Compared to VR systems, which present the user with a virtualenvironment while obscuring the real environment, a mixed reality systempresenting a MRE affords the advantage that the real environment remainsperceptible while the virtual environment is presented. Accordingly, theuser of the mixed reality system is able to use visual and audio cuesassociated with the real environment to experience and interact with thecorresponding virtual environment. As an example, while a user of VRsystems may struggle to perceive or interact with a virtual objectdisplayed in a virtual environment—because, as noted herein, a user maynot directly perceive or interact with a virtual environment—a user ofan MR system may find it more intuitive and natural to interact with avirtual object by seeing, hearing, and touching a corresponding realobject in his or her own real environment. This level of interactivitymay heighten a user's feelings of immersion, connection, and engagementwith a virtual environment. Similarly, by simultaneously presenting areal environment and a virtual environment, mixed reality systems mayreduce negative psychological feelings (e.g., cognitive dissonance) andnegative physical feelings (e.g., motion sickness) associated with VRsystems. Mixed reality systems further offer many possibilities forapplications that may augment or alter our experiences of the realworld.

FIG. 1A illustrates an exemplary real environment 100 in which a user110 uses a mixed reality system 112. Mixed reality system 112 maycomprise a display (e.g., a transmissive display), one or more speakers,and one or more sensors (e.g., a camera), for example as describedherein. The real environment 100 shown comprises a rectangular room104A, in which user 110 is standing; and real objects 122A (a lamp),124A (a table), 126A (a sofa), and 128A (a painting). Room 104A may bespatially described with a location coordinate (e.g., coordinate system108); locations of the real environment 100 may be described withrespect to an origin of the location coordinate (e.g., point 106). Asshown in FIG. 1A, an environment/world coordinate system 108 (comprisingan x-axis 108X, a y-axis 108Y, and a z-axis 108Z) with its origin atpoint 106 (a world coordinate), can define a coordinate space for realenvironment 100. In some embodiments, the origin point 106 of theenvironment/world coordinate system 108 may correspond to where themixed reality system 112 was powered on. In some embodiments, the originpoint 106 of the environment/world coordinate system 108 may be resetduring operation. In some examples, user 110 may be considered a realobject in real environment 100; similarly, user 110's body parts (e.g.,hands, feet) may be considered real objects in real environment 100. Insome examples, a user/listener/head coordinate system 114 (comprising anx-axis 114X, a y-axis 114Y, and a z-axis 114Z) with its origin at point115 (e.g., user/listener/head coordinate) can define a coordinate spacefor the user/listener/head on which the mixed reality system 112 islocated. The origin point 115 of the user/listener/head coordinatesystem 114 may be defined relative to one or more components of themixed reality system 112. For example, the origin point 115 of theuser/listener/head coordinate system 114 may be defined relative to thedisplay of the mixed reality system 112 such as during initialcalibration of the mixed reality system 112. A matrix (which may includea translation matrix and a quaternion matrix, or other rotation matrix),or other suitable representation can characterize a transformationbetween the user/listener/head coordinate system 114 space and theenvironment/world coordinate system 108 space. In some embodiments, aleft ear coordinate 116 and a right ear coordinate 117 may be definedrelative to the origin point 115 of the user/listener/head coordinatesystem 114. A matrix (which may include a translation matrix and aquaternion matrix, or other rotation matrix), or other suitablerepresentation can characterize a transformation between the left earcoordinate 116 and the right ear coordinate 117, and user/listener/headcoordinate system 114 space. The user/listener/head coordinate system114 can simplify the representation of locations relative to the user'shead, or to a head-mounted device, for example, relative to theenvironment/world coordinate system 108. Using Simultaneous Localizationand Mapping (SLAM), visual odometry, or other techniques, atransformation between user coordinate system 114 and environmentcoordinate system 108 can be determined and updated in real-time.

FIG. 1B illustrates an exemplary virtual environment 130 thatcorresponds to real environment 100. The virtual environment 130 showncomprises a virtual rectangular room 104B corresponding to realrectangular room 104A; a virtual object 122B corresponding to realobject 122A; a virtual object 124B corresponding to real object 124A;and a virtual object 126B corresponding to real object 126A. Metadataassociated with the virtual objects 122B, 124B, 126B can includeinformation derived from the corresponding real objects 122A, 124A,126A. Virtual environment 130 additionally comprises a virtual character132, which may not correspond to any real object in real environment100. Real object 128A in real environment 100 may not correspond to anyvirtual object in virtual environment 130. A persistent coordinatesystem 133 (comprising an x-axis 133X, a y-axis 133Y, and a z-axis 133Z)with its origin at point 134 (persistent coordinate), can define acoordinate space for virtual content. The origin point 134 of thepersistent coordinate system 133 may be defined relative/with respect toone or more real objects, such as the real object 126A. A matrix (whichmay include a translation matrix and a quaternion matrix, or otherrotation matrix), or other suitable representation can characterize atransformation between the persistent coordinate system 133 space andthe environment/world coordinate system 108 space. In some embodiments,each of the virtual objects 122B, 124B, 126B, and 132 may have its ownpersistent coordinate point relative to the origin point 134 of thepersistent coordinate system 133. In some embodiments, there may bemultiple persistent coordinate systems and each of the virtual objects122B, 124B, 126B, and 132 may have its own persistent coordinate pointsrelative to one or more persistent coordinate systems.

Persistent coordinate data may be coordinate data that persists relativeto a physical environment. Persistent coordinate data may be used by MRsystems (e.g., MR system 112, 200) to place persistent virtual content,which may not be tied to movement of a display on which the virtualobject is being displayed. For example, a two-dimensional screen maydisplay virtual objects relative to a position on the screen. As thetwo-dimensional screen moves, the virtual content may move with thescreen. In some embodiments, persistent virtual content may be displayedin a corner of a room. A MR user may look at the corner, see the virtualcontent, look away from the corner (where the virtual content may nolonger be visible because the virtual content may have moved from withinthe user's field of view to a location outside the user's field of viewdue to motion of the user's head), and look back to see the virtualcontent in the corner (similar to how a real object may behave).

In some embodiments, persistent coordinate data (e.g., a persistentcoordinate system and/or a persistent coordinate frame) can include anorigin point and three axes. For example, a persistent coordinate systemmay be assigned to a center of a room by a MR system. In someembodiments, a user may move around the room, out of the room, re-enterthe room, etc., and the persistent coordinate system may remain at thecenter of the room (e.g., because it persists relative to the physicalenvironment). In some embodiments, a virtual object may be displayedusing a transform to persistent coordinate data, which may enabledisplaying persistent virtual content. In some embodiments, a MR systemmay use simultaneous localization and mapping to generate persistentcoordinate data (e.g., the MR system may assign a persistent coordinatesystem to a point in space). In some embodiments, a MR system may map anenvironment by generating persistent coordinate data at regularintervals (e.g., a MR system may assign persistent coordinate systems ina grid where persistent coordinate systems may be at least within fivefeet of another persistent coordinate system).

In some embodiments, persistent coordinate data may be generated by a MRsystem and transmitted to a remote server. In some embodiments, a remoteserver may be configured to receive persistent coordinate data. In someembodiments, a remote server may be configured to synchronize persistentcoordinate data from multiple observation instances. For example,multiple MR systems may map the same room with persistent coordinatedata and transmit that data to a remote server. In some embodiments, theremote server may use this observation data to generate canonicalpersistent coordinate data, which may be based on the one or moreobservations. In some embodiments, canonical persistent coordinate datamay be more accurate and/or reliable than a single observation ofpersistent coordinate data. In some embodiments, canonical persistentcoordinate data may be transmitted to one or more MR systems. Forexample, a MR system may use image recognition and/or location data torecognize that it is located in a room that has corresponding canonicalpersistent coordinate data (e.g., because other MR systems havepreviously mapped the room). In some embodiments, the MR system mayreceive canonical persistent coordinate data corresponding to itslocation from a remote server.

With respect to FIGS. 1A and 1B, environment/world coordinate system 108defines a shared coordinate space for both real environment 100 andvirtual environment 130. In the example shown, the coordinate space hasits origin at point 106. Further, the coordinate space is defined by thesame three orthogonal axes (108X, 108Y, 108Z). Accordingly, a firstlocation in real environment 100, and a second, corresponding locationin virtual environment 130, can be described with respect to the samecoordinate space. This simplifies identifying and displayingcorresponding locations in real and virtual environments, because thesame coordinates can be used to identify both locations. However, insome examples, corresponding real and virtual environments need not usea shared coordinate space. For instance, in some examples (not shown), amatrix (which may include a translation matrix and a quaternion matrix,or other rotation matrix), or other suitable representation cancharacterize a transformation between a real environment coordinatespace and a virtual environment coordinate space.

FIG. 1C illustrates an exemplary MRE 150 that simultaneously presentsaspects of real environment 100 and virtual environment 130 to user 110via mixed reality system 112. In the example shown, MRE 150simultaneously presents user 110 with real objects 122A, 124A, 126A, and128A from real environment 100 (e.g., via a transmissive portion of adisplay of mixed reality system 112); and virtual objects 122B, 124B,126B, and 132 from virtual environment 130 (e.g., via an active displayportion of the display of mixed reality system 112). As describedherein, origin point 106 acts as an origin for a coordinate spacecorresponding to MRE 150, and coordinate system 108 defines an x-axis,y-axis, and z-axis for the coordinate space.

In the example shown, mixed reality objects comprise corresponding pairsof real objects and virtual objects (e.g., 122A/122B, 124A/124B,126A/126B) that occupy corresponding locations in coordinate space 108.In some examples, both the real objects and the virtual objects may besimultaneously visible to user 110. This may be desirable in, forexample, instances where the virtual object presents informationdesigned to augment a view of the corresponding real object (such as ina museum application where a virtual object presents the missing piecesof an ancient damaged sculpture). In some examples, the virtual objects(122B, 124B, and/or 126B) may be displayed (e.g., via active pixelatedocclusion using a pixelated occlusion shutter) so as to occlude thecorresponding real objects (122A, 124A, and/or 126A). This may bedesirable in, for example, instances where the virtual object acts as avisual replacement for the corresponding real object (such as in aninteractive storytelling application where an inanimate real objectbecomes a “living” character).

In some examples, real objects (e.g., 122A, 124A, 126A) may beassociated with virtual content or helper data that may not necessarilyconstitute virtual objects. Virtual content or helper data canfacilitate processing or handling of virtual objects in the mixedreality environment. For example, such virtual content could includetwo-dimensional representations of corresponding real objects; customasset types associated with corresponding real objects; or statisticaldata associated with corresponding real objects. This information canenable or facilitate calculations involving a real object withoutincurring unnecessary computational overhead.

In some examples, the presentation described herein may also incorporateaudio aspects. For instance, in MRE 150, virtual character 132 could beassociated with one or more audio signals, such as a footstep soundeffect that is generated as the character walks around MRE 150. Asdescribed herein, a processor of mixed reality system 112 can compute anaudio signal corresponding to a mixed and processed composite of allsuch sounds in MRE 150, and present the audio signal to user 110 via oneor more speakers included in mixed reality system 112 and/or one or moreexternal speakers.

Example mixed reality system 112 can include a wearable head device(e.g., a wearable augmented reality or mixed reality head device)comprising a display (which may comprise left and right transmissivedisplays, which may be near-eye displays, and associated components forcoupling light from the displays to the user's eyes); left and rightspeakers (e.g., positioned adjacent to the user's left and right ears,respectively); an inertial measurement unit (IMU) (e.g., mounted to atemple arm of the head device); an orthogonal coil electromagneticreceiver (e.g., mounted to the left temple piece); left and rightcameras (e.g., depth (time-of-flight) cameras) oriented away from theuser; and left and right eye cameras oriented toward the user (e.g., fordetecting the user's eye movements). However, a mixed reality system 112can incorporate any suitable display technology, and any suitablesensors (e.g., optical, infrared, acoustic, LIDAR, EOG, GPS, magnetic).In addition, mixed reality system 112 may incorporate networkingfeatures (e.g., Wi-Fi capability, mobile network (e.g., 4G, 5G)capability) to communicate with other devices and systems, includingneural networks (e.g., in the cloud) for data processing and trainingdata associated with presentation of elements (e.g., virtual character132) in the MRE 150 and other mixed reality systems. Mixed realitysystem 112 may further include a battery (which may be mounted in anauxiliary unit, such as a belt pack designed to be worn around a user'swaist), a processor, and a memory. The wearable head device of mixedreality system 112 may include tracking components, such as an IMU orother suitable sensors, configured to output a set of coordinates of thewearable head device relative to the user's environment. In someexamples, tracking components may provide input to a processorperforming a Simultaneous Localization and Mapping (SLAM) and/or visualodometry algorithm. In some examples, mixed reality system 112 may alsoinclude a handheld controller 300, and/or an auxiliary unit 320, whichmay be a wearable beltpack, as described herein.

In some embodiments, an animation rig is used to present the virtualcharacter 132 in the MRE 150. Although the animation rig is describedwith respect to virtual character 132, it is understood that theanimation rig may be associated with other characters (e.g., a humancharacter, an animal character, an abstract character) in the MRE 150.Movement of the animation rig is described in more detail herein.

FIGS. 2A-2D illustrate components of an exemplary mixed reality system200 (which may correspond to mixed reality system 112) that may be usedto present a MRE (which may correspond to MRE 150), or other virtualenvironment, to a user. FIG. 2A illustrates a perspective view of awearable head device 2102 included in example mixed reality system 200.FIG. 2B illustrates a top view of wearable head device 2102 worn on auser's head 2202. FIG. 2C illustrates a front view of wearable headdevice 2102. FIG. 2D illustrates an edge view of example eyepiece 2110of wearable head device 2102. As shown in FIGS. 2A-2C, the examplewearable head device 2102 includes an exemplary left eyepiece (e.g., aleft transparent waveguide set eyepiece) 2108 and an exemplary righteyepiece (e.g., a right transparent waveguide set eyepiece) 2110. Eacheyepiece 2108 and 2110 can include transmissive elements through which areal environment can be visible, as well as display elements forpresenting a display (e.g., via imagewise modulated light) overlappingthe real environment. In some examples, such display elements caninclude surface diffractive optical elements for controlling the flow ofimagewise modulated light. For instance, the left eyepiece 2108 caninclude a left incoupling grating set 2112, a left orthogonal pupilexpansion (OPE) grating set 2120, and a left exit (output) pupilexpansion (EPE) grating set 2122. Similarly, the right eyepiece 2110 caninclude a right incoupling grating set 2118, a right OPE grating set2114 and a right EPE grating set 2116. Imagewise modulated light can betransferred to a user's eye via the incoupling gratings 2112 and 2118,OPEs 2114 and 2120, and EPE 2116 and 2122. Each incoupling grating set2112, 2118 can be configured to deflect light toward its correspondingOPE grating set 2120, 2114. Each OPE grating set 2120, 2114 can bedesigned to incrementally deflect light down toward its associated EPE2122, 2116, thereby horizontally extending an exit pupil being formed.Each EPE 2122, 2116 can be configured to incrementally redirect at leasta portion of light received from its corresponding OPE grating set 2120,2114 outward to a user eyebox position (not shown) defined behind theeyepieces 2108, 2110, vertically extending the exit pupil that is formedat the eyebox. Alternatively, in lieu of the incoupling grating sets2112 and 2118, OPE grating sets 2114 and 2120, and EPE grating sets 2116and 2122, the eyepieces 2108 and 2110 can include other arrangements ofgratings and/or refractive and reflective features for controlling thecoupling of imagewise modulated light to the user's eyes.

In some examples, wearable head device 2102 can include a left templearm 2130 and a right temple arm 2132, where the left temple arm 2130includes a left speaker 2134 and the right temple arm 2132 includes aright speaker 2136. An orthogonal coil electromagnetic receiver 2138 canbe located in the left temple piece, or in another suitable location inthe wearable head unit 2102. An Inertial Measurement Unit (IMU) 2140 canbe located in the right temple arm 2132, or in another suitable locationin the wearable head device 2102. The wearable head device 2102 can alsoinclude a left depth (e.g., time-of-flight) camera 2142 and a rightdepth camera 2144. The depth cameras 2142, 2144 can be suitably orientedin different directions so as to together cover a wider field of view.

In the example shown in FIGS. 2A-2D, a left source of imagewisemodulated light 2124 can be optically coupled into the left eyepiece2108 through the left incoupling grating set 2112, and a right source ofimagewise modulated light 2126 can be optically coupled into the righteyepiece 2110 through the right incoupling grating set 2118. Sources ofimagewise modulated light 2124, 2126 can include, for example, opticalfiber scanners; projectors including electronic light modulators such asDigital Light Processing (DLP) chips or Liquid Crystal on Silicon (LCoS)modulators; or emissive displays, such as micro Light Emitting Diode(μLED) or micro Organic Light Emitting Diode (μOLED) panels coupled intothe incoupling grating sets 2112, 2118 using one or more lenses perside. The input coupling grating sets 2112, 2118 can deflect light fromthe sources of imagewise modulated light 2124, 2126 to angles above thecritical angle for Total Internal Reflection (TIR) for the eyepieces2108, 2110. The OPE grating sets 2114, 2120 incrementally deflect lightpropagating by TIR down toward the EPE grating sets 2116, 2122. The EPEgrating sets 2116, 2122 incrementally couple light toward the user'sface, including the pupils of the user's eyes.

In some examples, as shown in FIG. 2D, each of the left eyepiece 2108and the right eyepiece 2110 includes a plurality of waveguides 2402. Forexample, each eyepiece 2108, 2110 can include multiple individualwaveguides, each dedicated to a respective color channel (e.g., red,blue. and green). In some examples, each eyepiece 2108, 2110 can includemultiple sets of such waveguides, with each set configured to impartdifferent wavefront curvature to emitted light. The wavefront curvaturemay be convex with respect to the user's eyes, for example to present avirtual object positioned a distance in front of the user (e.g., by adistance corresponding to the reciprocal of wavefront curvature). Insome examples, EPE grating sets 2116, 2122 can include curved gratinggrooves to effect convex wavefront curvature by altering the Poyntingvector of exiting light across each EPE.

In some examples, to create a perception that displayed content isthree-dimensional, stereoscopically-adjusted left and right eye imagerycan be presented to the user through the imagewise light modulators2124, 2126 and the eyepieces 2108, 2110. The perceived realism of apresentation of a three-dimensional virtual object can be enhanced byselecting waveguides (and thus corresponding the wavefront curvatures)such that the virtual object is displayed at a distance approximating adistance indicated by the stereoscopic left and right images. Thistechnique may also reduce motion sickness experienced by some users,which may be caused by differences between the depth perception cuesprovided by stereoscopic left and right eye imagery, and the autonomicaccommodation (e.g., object distance-dependent focus) of the human eye.

FIG. 2D illustrates an edge-facing view from the top of the righteyepiece 2110 of example wearable head device 2102. As shown in FIG. 2D,the plurality of waveguides 2402 can include a first subset of threewaveguides 2404 and a second subset of three waveguides 2406. The twosubsets of waveguides 2404, 2406 can be differentiated by different EPEgratings featuring different grating line curvatures to impart differentwavefront curvatures to exiting light. Within each of the subsets ofwaveguides 2404, 2406 each waveguide can be used to couple a differentspectral channel (e.g., one of red, green and blue spectral channels) tothe user's right eye 2206. Although not shown in FIG. 2D, the structureof the left eyepiece 2108 may be mirrored relative to the structure ofthe right eyepiece 2110.

FIG. 3A illustrates an exemplary handheld controller component 300 of amixed reality system 200. In some examples, handheld controller 300includes a grip portion 346 and one or more buttons 350 disposed along atop surface 348. In some examples, buttons 350 may be configured for useas an optical tracking target, e.g., for tracking six-degree-of-freedom(6DOF) motion of the handheld controller 300, in conjunction with acamera or other optical sensor (which may be mounted in a head unit(e.g., wearable head device 2102) of mixed reality system 200). In someexamples, handheld controller 300 includes tracking components (e.g., anIMU or other suitable sensors) for detecting position or orientation,such as position or orientation relative to wearable head device 2102.In some examples, such tracking components may be positioned in a handleof handheld controller 300, and/or may be mechanically coupled to thehandheld controller. Handheld controller 300 can be configured toprovide one or more output signals corresponding to one or more of apressed state of the buttons; or a position, orientation, and/or motionof the handheld controller 300 (e.g., via an IMU). Such output signalsmay be used as input to a processor of mixed reality system 200. Suchinput may correspond to a position, orientation, and/or movement of thehandheld controller (and, by extension, to a position, orientation,and/or movement of a hand of a user holding the controller). Such inputmay also correspond to a user pressing buttons 350.

FIG. 3B illustrates an exemplary auxiliary unit 320 of a mixed realitysystem 200. The auxiliary unit 320 can include a battery to provideenergy to operate the system 200, and can include a processor forexecuting programs to operate the system 200. As shown, the exampleauxiliary unit 320 includes a clip 2128, such as for attaching theauxiliary unit 320 to a user's belt. Other form factors are suitable forauxiliary unit 320 and will be apparent, including form factors that donot involve mounting the unit to a user's belt. In some examples,auxiliary unit 320 is coupled to the wearable head device 2102 through amulticonduit cable that can include, for example, electrical wires andfiber optics. Wireless connections between the auxiliary unit 320 andthe wearable head device 2102 can also be used.

In some examples, mixed reality system 200 can include one or moremicrophones to detect sound and provide corresponding signals to themixed reality system. In some examples, a microphone may be attached to,or integrated with, wearable head device 2102, and may be configured todetect a user's voice. In some examples, a microphone may be attachedto, or integrated with, handheld controller 300 and/or auxiliary unit320. Such a microphone may be configured to detect environmental sounds,ambient noise, voices of a user or a third party, or other sounds.

FIG. 4 shows an exemplary functional block diagram that may correspondto an exemplary mixed reality system, such as mixed reality system 200described herein (which may correspond to mixed reality system 112 withrespect to FIG. 1). Elements of wearable system 400 may be used toimplement the methods, operations, and features described in thisdisclosure. As shown in FIG. 4, example handheld controller 400B (whichmay correspond to handheld controller 300 (a “totem”)) includes atotem-to-wearable head device six degree of freedom (6DOF) totemsubsystem 404A and example wearable head device 400A (which maycorrespond to wearable head device 2102) includes a totem-to-wearablehead device 6DOF subsystem 404B. In the example, the 6DOF totemsubsystem 404A and the 6DOF subsystem 404B cooperate to determine sixcoordinates (e.g., offsets in three translation directions and rotationalong three axes) of the handheld controller 400B relative to thewearable head device 400A. The six degrees of freedom may be expressedrelative to a coordinate system of the wearable head device 400A. Thethree translation offsets may be expressed as X, Y, and Z offsets insuch a coordinate system, as a translation matrix, or as some otherrepresentation. The rotation degrees of freedom may be expressed assequence of yaw, pitch, and roll rotations, as a rotation matrix, as aquaternion, or as some other representation. In some examples, thewearable head device 400A; one or more depth cameras 444 (and/or one ormore non-depth cameras) included in the wearable head device 400A;and/or one or more optical targets (e.g., buttons 350 of handheldcontroller 400B as described herein, or dedicated optical targetsincluded in the handheld controller 400B) can be used for 6DOF tracking.In some examples, the handheld controller 400B can include a camera, asdescribed herein; and the wearable head device 400A can include anoptical target for optical tracking in conjunction with the camera. Insome examples, the wearable head device 400A and the handheld controller400B each include a set of three orthogonally oriented solenoids whichare used to wirelessly send and receive three distinguishable signals.By measuring the relative magnitude of the three distinguishable signalsreceived in each of the coils used for receiving, the 6DOF of thewearable head device 400A relative to the handheld controller 400B maybe determined. Additionally, 6DOF totem subsystem 404A can include anInertial Measurement Unit (IMU) that is useful to provide improvedaccuracy and/or more timely information on rapid movements of thehandheld controller 400B.

In some embodiments, wearable system 400 can include microphone array407, which can include one or more microphones arranged on headgeardevice 400A. In some embodiments, microphone array 407 can include fourmicrophones. Two microphones can be placed on a front face of headgear400A, and two microphones can be placed at a rear of head headgear 400A(e.g., one at a back-left and one at a back-right). In some embodiments,signals received by microphone array 407 can be transmitted to DSP 408.DSP 408 can be configured to perform signal processing on the signalsreceived from microphone array 407. For example, DSP 408 can beconfigured to perform noise reduction, acoustic echo cancellation,and/or beamforming on signals received from microphone array 407. DSP408 can be configured to transmit signals to processor 416.

In some examples, it may become necessary to transform coordinates froma local coordinate space (e.g., a coordinate space fixed relative to thewearable head device 400A) to an inertial coordinate space (e.g., acoordinate space fixed relative to the real environment), for example inorder to compensate for the movement of the wearable head device 400A(e.g., of MR system 112) relative to the coordinate system 108. Forinstance, such transformations may be necessary for a display of thewearable head device 400A to present a virtual object at an expectedposition and orientation relative to the real environment (e.g., avirtual person sitting in a real chair, facing forward, regardless ofthe wearable head device's position and orientation), rather than at afixed position and orientation on the display (e.g., at the sameposition in the right lower corner of the display), to preserve theillusion that the virtual object exists in the real environment (anddoes not, for example, appear positioned unnaturally in the realenvironment as the wearable head device 400A shifts and rotates). Insome examples, a compensatory transformation between coordinate spacescan be determined by processing imagery from the depth cameras 444 usinga SLAM and/or visual odometry procedure in order to determine thetransformation of the wearable head device 400A relative to thecoordinate system 108. In the example shown in FIG. 4, the depth cameras444 are coupled to a SLAM/visual odometry block 406 and can provideimagery to block 406. The SLAM/visual odometry block 406 implementationcan include a processor configured to process this imagery and determinea position and orientation of the user's head, which can then be used toidentify a transformation between a head coordinate space and anothercoordinate space (e.g., an inertial coordinate space). Similarly, insome examples, an additional source of information on the user's headpose and location is obtained from an IMU 409. Information from the IMU409 can be integrated with information from the SLAM/visual odometryblock 406 to provide improved accuracy and/or more timely information onrapid adjustments of the user's head pose and position.

In some examples, the depth cameras 444 can supply 3D imagery to a handgesture tracker 411, which may be implemented in a processor of thewearable head device 400A. The hand gesture tracker 411 can identify auser's hand gestures, for example by matching 3D imagery received fromthe depth cameras 444 to stored patterns representing hand gestures.Other suitable techniques of identifying a user's hand gestures will beapparent.

In some examples, one or more processors 416 may be configured toreceive data from the wearable head device's 6DOF headgear subsystem404B, the IMU 409, the SLAM/visual odometry block 406, depth cameras444, and/or the hand gesture tracker 411. The processor 416 can alsosend and receive control signals from the 6DOF totem system 404A. Theprocessor 416 may be coupled to the 6DOF totem system 404A wirelessly,such as in examples where the handheld controller 400B is untethered.Processor 416 may further communicate with additional components, suchas an audio-visual content memory 418, a Graphical Processing Unit (GPU)420, and/or a Digital Signal Processor (DSP) audio spatializer 422. TheDSP audio spatializer 422 may be coupled to a Head Related TransferFunction (HRTF) memory 425. The GPU 420 can include a left channeloutput coupled to the left source of imagewise modulated light 424 and aright channel output coupled to the right source of imagewise modulatedlight 426. GPU 420 can output stereoscopic image data to the sources ofimagewise modulated light 424, 426, for example as described herein withrespect to FIGS. 2A-2D. In some examples, the GPU 420 may be used torender virtual elements in the MRE presented on the display of thewearable system 400. The DSP audio spatializer 422 can output audio to aleft speaker 412 and/or a right speaker 414. The DSP audio spatializer422 can receive input from processor 419 indicating a direction vectorfrom a user to a virtual sound source (which may be moved by the user,e.g., via the handheld controller 320). Based on the direction vector,the DSP audio spatializer 422 can determine a corresponding HRTF (e.g.,by accessing a HRTF, or by interpolating multiple HRTFs). The DSP audiospatializer 422 can then apply the determined HRTF to an audio signal,such as an audio signal corresponding to a virtual sound generated by avirtual object. This can enhance the believability and realism of thevirtual sound, by incorporating the relative position and orientation ofthe user relative to the virtual sound in the mixed realityenvironment—that is, by presenting a virtual sound that matches a user'sexpectations of what that virtual sound would sound like if it were areal sound in a real environment.

In some embodiments, the graphics in the mixed reality environment(e.g., the virtual character) may be rendered using “Forward+,” which isa version of a desktop renderer without a G-buffer. As an exemplaryadvantage, Forward+ include a wider choice of lighting and surfaceshading models, compute-shader optimized skinning and post-morph-targetnormal recalculations, and more post-processing options, compared to amobile renderer. Using such a renderer and with access to engine sourcecode, custom changes to character-related engine features and shadingmodels may be made. Additionally, Forward+ may free the mixed realitysystem from bottleneck due to the lack of a G-buffer and allowingotherwise unused cycles on the GPU (e.g., GPU 420) to be utilized. Incontrast, rendering in full deferred mode and maintaining graphics at 60frames per second in stereo may leave the mixed reality system littleroom for other runtime computation.

In some embodiments, the hardware and software stack of the mixedreality system supports a graphics application programming interfacesuch as Vulkan. As an exemplary advantage, Vulkan may free up room onthe CPU and allowed the system to shuffle allocations of CPU and GPUresources to get achieve better performance (e.g., over 60 frames persecond stereo).

In some examples, such as shown in FIG. 4, one or more of processor 416,GPU 420, DSP audio spatializer 422, HRTF memory 425, and audio/visualcontent memory 418 may be included in an auxiliary unit 400C (which maycorrespond to auxiliary unit 320 described herein). The auxiliary unit400C may include a battery 427 to power its components and/or to supplypower to the wearable head device 400A or handheld controller 400B.Including such components in an auxiliary unit, which can be mounted toa user's waist, can limit the size and weight of the wearable headdevice 400A, which can in turn reduce fatigue of a user's head and neck.

While FIG. 4 presents elements corresponding to various components of anexample wearable systems 400, various other suitable arrangements ofthese components will become apparent to those skilled in the art. Forexample, the headgear device 400A illustrated in may include a processorand/or a battery (not shown). The included processor and/or battery mayoperate together with or operate in place of the processor and/orbattery of the auxiliary unit 400C. Generally, as another example,elements presented or functionalities described with respect to FIG. 4as being associated with auxiliary unit 400C could instead be associatedwith headgear device 400A or handheld controller 400B. Furthermore, somewearable systems may forgo entirely a handheld controller 400B orauxiliary unit 400C. Such changes and modifications are to be understoodas being included within the scope of the disclosed examples.

FIG. 5 illustrates an exemplary character in a mixed realityenvironment, according to embodiments of the disclosure. The virtualcharacter 500 may be an autonomous and photoreal human character knownor referred to as “Mica.” The character 500 may be configured to bepresented on a display of a mixed reality system (e.g., mixed realitysystem 112, mixed reality system 200, wearable system 400). For example,the character 500 may be virtual character 132 in the MRE 150. In someembodiments, an animation rig is used to present the virtual character132 in the MRE 150. Although the face and neck of the virtual character500 is shown in FIG. 5, it is understood that the descriptions of thevirtual character 500 may be applicable to the entire body of thecharacter.

The character 500 may be based on a composite of different individualhumans. The character 500 may include artistic designs unique to thecharacter. The base 3D models and textures of the character may beacquired by scanning actors in a high-resolution photogrammetry system.The scanned models may then be artistically sculpted into the character.The character 500 may be derived from a level-of-detail (LOD) chainanchored by a high-quality, “VFX style” asset that can be renderedoffline in a path tracer, and the realism of the character may bevalidated (e.g., by the designer). For quality control and referencepurposes, it may be important to have a target look for the character atthis level. For instance, when making changes to the character 500, thetop-most of the LOD chain is updated, the changes migrate down, ratherthan changing directly in a lower LOD. The created character may beimported into a game engine such as Unreal Engine 4 to create animationfor the character in the mixed reality environment (e.g., MRE 150). Asan exemplary advantage, the created character may be used acrossdifferent platforms or later versions of a platform without substantialupdates to the character between the different platforms or thedifferent versions.

In some embodiments, facial geometry and expressiveness of character 500are emphasized over other features of the character to optimizecomputing efficiency (e.g., to reduce computing resources associatedwith these other features). For instance, the user may be standingface-to-face with the character 500. The user may pick up on the shapeof the character's smile and the glint in the eyes, so emphasis on thesefeatures may allow a more immersive user experience while maintainingcomputing efficiency. In some embodiments, less emphasis may put placedon global illumination or individual strands of hair; computations ofthese character features may be intensive and consume device power withless benefits for user experience. To reduce emphasis while maximizingquality, for example, the virtual character's dense hair groom may beconverted to polygon strips to improve performance. Although the hair ofthe virtual character may not be dynamic, the polygon hair strips mayreact to facial expressions and head motion using synchronizedblendshapes. A blendshape may allow a single mesh of an animation rig todeform to achieve numerous pre-defined shapes and any number ofcombinations of in-between these shapes. To give the hair a morelife-like appearance, a custom hair shader may be used in place of ahair shader provided by a game engine, such as Unreal Engine 4.

In some embodiments, an animation rig is used to present the virtualcharacter 132 in the MRE 150. For example, the animation rig may becreated using a graphics application such as Maya. It is understood thatother graphics application may be used to build the animation rig. Inthe graphics application, characteristics of the animation rig such asskin clusters, custom blendshape node, specific constraints,expressions, custom mesh-to-mesh collision, clothing simulation, hairsimulation, Delta Mush deformation, and control systems such as FacialAction Coding System (FACS) combo shapes, blendshape weights, and jointtransforms are defined.

In some embodiments, FACS based blendshapes are used in animating thecharacter's facial features, which includes over 120 FACS shapes and anadditional 800 shapes combined from the 120 FACS shapes. After theanimation rig is created, a logic node may include a custom rule basedsystem to manage combinatorial logic for these shapes, and to captureprocedural relationships, such as set driven keys. The logic node alsoprovide an expression language and capture connections and dependenciesbetween features of the animation rig (e.g., mathematical expressions,pose coordinates). The logic node may also generate a C++ engine codebased on the animation rig, which is compiled for realtime execution(e.g., when a character is presented in a mixed reality environment).

The deformation of the eyes, tongue, teeth, jaw, head, and neck may bedriven by blendshapes and linear blend skinning. This skinning of thebody and clothing may be computed by manually creating example poses anda set of joints, and solving for the joint positions (e.g., spatialrelationships) and skin weights with convex quadratic programming.

In some embodiments, body deformations are created using a layeredscheme with a base skeleton (e.g., primary joints) driving a higherlevel system of joints (e.g., helper joints). These joints may driveblendshape and skinning based deformations. Clothing simulations may berun with a range of motion animation sequence, and presentation of theresulting deformations may be computed.

The methods and features described herein allow characteristics of theanimation rig created in the graphics application to be efficientlypresented in a mixed reality system, such as mixed reality system 112,mixed reality system 200, or wearable system 400, which may havehardware limitations such as power consumption requirements and limitedprocessing resources (e.g., a mobile CPU may be running the mixedreality system, the system may have a 1 ms/frame budget), for example,to maintain the portability of the system. Biomechanics behaviors anddeformation of the character 500 may be more important to create animmersive user experience. As such, processing resources may be morefocused on presentation of character biomechanics behaviors anddeformation.

The animation rig may comprise primary joints and helper joints. At aparticular time, the animation rig may be a pose, and the pose may bedefined by spatial relationships between the primary joints and thehelper joints (e.g., distances, angles relative to each other).

The primary joints may be associated with skeletal joints of a character(e.g., character 500). For example, the primary joint locations mayinclude shoulders, elbows, wrists, knees, and ankles of the character500. It is understood that the term “joint” is not meant to limiting;primary joints and helper joints may be located at non-skeletal jointlocations (e.g., midpoint of a femur, top of the head).

FIG. 6 illustrates an exemplary animation rig 600 in a mixed realitysystem, according to embodiments of the disclosure. The animation rig600 includes helper joints 602-608. The helper joints may be driven by amain skeleton (e.g., including primary joints 610 and 612) of theanimation rig and create secondary deformations such as muscle bulging,skin sliding, soft tissue deformations, and rigid bone deformations. Forexample, helper joints 602 and 604 may be associated with bicep andtricep muscles of the character 500. When the elbow bends, the motion ofthe helper joints causes the muscles to appear to be bulging. Helperjoints 606 and 608 may be associated with rigid motion of the ulna bone.As an exemplary advantage, using helper joints would reduce computationcost and power consumption, compared to using blendshapes, whilepresenting a life-like animation to the user of the mixed realitysystem.

The helper joints may be associated with locations of the animation rigdetermined by a helper joint placement criterion. In some embodiments,the helper joints is located at locations associated with largedisplacement between primary joints. For example, a helper joint may belocated near the biceps of the character 500 between the wrist and theelbow (e.g., primary joints) because the biceps may experience a largerdisplacement for a particular movement associated with the shoulder andthe elbow, compared to other locations of the character between theshoulder and the elbow. As another example, a helper joint may belocated near the calves of the character 500 between the ankle and theknee (e.g., primary joints) because the calves may experience a largerdisplacement for a particular movement associated with the ankle and theknee, compared to other locations of the character between the ankle andthe knee. In these examples, the locations of the helper joints at thebiceps or the calves may be determined by a maximum movement criterion.

Although the movements and interactions of primary joints and helperjoints are described with respect to the character's limbs, it isunderstand these exemplary movements and interactions are not limiting.For example, primary joints and helper joints may advantageously drivethe virtual character's facial expressions.

In some examples, blendshapes may have too many moving points andinverted targets may not interpolate well. Using all blendshapes toanimate the virtual character 500 may cause a large performance penaltyat runtime. Helper joints may reduce this performance impact byconverting shape information, normally handled by blendshapes, into skinclusters using a joint decomposition process. In some embodiments, thedecomposition process calculates positions of the helper joints for eachblendshape to match blendshape deformations. Additionally, skin weightsof a skin cluster associate with each helper joint and each blendshapepose may be optimized to further improve the realism of thedeformations. The skin clusters may be incorporated with a fewer numberof blendshapes to remove undesirable high frequency features on thevirtual character. Incorporating helper joints and skin clusters withfewer blendshapes may advantageously improve system performance andinterpolation between poses due to smaller displacements, compared tousing exclusively blendshapes, while maintaining a similar level ofquality.

In some embodiments, the helper joint may be manually defined, forexample, by designer of the character 500. For example, the designer maydecide that manually defining a helper joint would allow the character500 to become more “life-like.”

The animation rig may be determined to move from a first pose at a firsttime to a second pose at a second time. For example, the mixed realitysystem may determine that the character 500 is moving from a firstposition to a second position in the mixed reality environment (e.g.,MRE 150) to perform an action. At the first time, the animation rig maybe in a first pose associated with the character in a first position(e.g., the character is not smiling, the character is sitting, thecharacter is standing), and the first pose may be defined by firstspatial relationships between the primary joints and helper joints ofthe character. At the second time, the character may move from the firstposition to a second position (e.g., the character is smiling, thecharacter is standing, the character is walking); the animation rig maybe in a second pose associated with the character in the secondposition, and the second pose may be defined by second spatialrelationships between the primary joints and helper joints of thecharacter. The first and second spatial relationships may be differentbecause the first and second positions of the character are different.The display of the mixed reality system may be updated to present thecharacter 500 in the second position based on the animation rig's secondpose defined by the second spatial relationships between the character'sprimary joints and helper joints.

The transformation from the animation rig's first pose to the secondpose may be defined by movement information. For example, the movementinformation may define movements of primary joints and helper joints andmovements of character features between primary and helper joints fromthe first pose to the second pose. The movements of character featuresbetween primary and helper joints from the first pose to the second posemay be interpolated (e.g., determined using regression analysis), andthe interpolation may be determined using the methods disclosed herein.

To create life-like biomechanics for the character, the spatialrelationships between primary joints and helper joints may be complexand non-linear (e.g., the helper joints may be driven by constraints andexpressions from the graphics application). The relationships may bedefined with a radial basis function (RBF), which may require a largeamount of samples. For example, in the deltoid-pectoral region, over1100 poses may be required on each side to achieve a desirable qualityusing RBF. The large amount of samples may affect runtime performance ofthe mixed reality system, which may have power and computing resourcerestraints. Furthermore, using RBF to define relationships between theprimary joints and helper joints may not satisfy a requirement (e.g., 6ms per frame) of the mixed reality system. Therefore, it may bedesirable to use a more efficient method (e.g., less computationallyintensive) to present a virtual character in a high-quality manner.

In some embodiments, information associated with the animation rig'smovement is transmitted to a neural network for processing. In someembodiments, information associated with the animation rig's movement istransmitted to more than one neural network for processing. The neuralnetwork receives the information associated with the animation rig'smovement, computes the movement information, and transmits the movementinformation to the mixed reality system to present the movement of thevirtual character on the display of the system based on the movementinformation.

In some embodiments, the movement information is further computed usingtraining data presented to the neural network (e.g., by a rig designer,by a user). The training data may include animation data such as a rangeof motion test. The training data may cover poses and movements that avirtual character may perform in a mixed reality environment. Forexample, the training data includes examples of knee twists, and theneural network may compute movement information (e.g., rotationalinformation associated with the knee joint) using these examples of kneetwists. In some embodiments, the training data for a set of helperjoints may primary comprises of a range-of-motion animation sequence andother example sequences. A number of hidden dimensions to use may bedetermined using hyper-parameter tuning. In some examples, the number ofhidden dimensions may be ten times a maximum of a number of primaryjoints and a number of helper joints.

As an exemplary advantage, using the neural network to compute themovement information can reduce a number of parameters to achievepresentation of virtual character having a similar high quality,compared to using RBF parameters, because a neural network may includefewer trainable parameters (e.g., a factor of 28 times reduction). Forexample, for a similar quality presentation of the virtual character,4.5 million parameters may be needed using RBF, but a significantlysmaller 160 thousand parameters may be needed using a neural network.

In some embodiments, the neural network uses rectified linear unit(ReLU) activation functions to compute the movement information.Compared to other activation functions, ReLU functions can be morecomputationally efficient, and convey other advantages. In someembodiments, the neural network may be a multilayer feedforward neuralnetwork. The neural network may be a fully connected network with onehidden layer between an input layer and an output layer of the network.The neural network may translate and scale using mean square error (MSE)loss. In some embodiments, a total of 66 separate networks may be usedcompute the movement information of the animation rig. For each jointcluster, each of the networks may be separately trained for translation,rotation, and scaling. In some embodiments, translation values arescaled or normalized to a 0 to 1 range for the neural network.

In some embodiments, rotations associated with the animation rig may berepresented with quaternions. Quaternions may be used for an animationsystem (e.g., Unreal) associated with presentation of the virtualcharacter in a mixed reality environment on a display of a mixed realitysystem. Furthermore, quaternions may be more suitable for parameterizingrotations for machine learning. Existing methods for computingquaternions in neural networks measure loss with Euclidean angles, orretain orientation ambiguities. In some embodiments, quaternion trainingdata may be cast to have a nonzero w component. Therefore, regressingquaternions may require a new loss function combining mean squared errorloss of the component values with a penalty for component values greaterthan 1, which may be represented with the following function:

μMSE(max(Y_(p)−1,0))  (1)

Because unit quaternions are used, no component should have a valuehigher than one. The training also clamps the magnitude of the gradientsused for back-propagation (e.g., gradient clipping) to prevent thenetwork from drifting to another pole. As an exemplary advantage,regressing quaternions using this described methodology allows the mixedreality system to run around 0.9 ms per frame. In some embodiments, thismethodology may be integrated as a custom Blueprint operator in a gameengine that executes as a TensorFlow Lite model running on a neuralnetwork or on the mixed reality system.

As an exemplary advantage, the character 500 may be configured topresented on a display of a mixed reality system (e.g., mixed realitysystem 112, mixed reality system 200, wearable system 400), which mayhave more hardware constraints compare to existing systems displayinghigh-end and real-time virtual characters due to the system'sportability. In some examples, the mixed reality system may bebattery-powered; thus, one of these hardware constraints may be power.Even with these hardware constraints, the methods described hereinenable creation of a convincing virtual character; rendering, animation,deformations, clothing, hair, and behavior are able to meet a certainintangible quality level for the character to be believable while alsofitting within the performance envelope of the hardware.

As mentioned, to improve a user's mixed reality experience, it isdesirable for the virtual character to be as life-like as possible. Inaddition to realistic movements, the virtual character may be presentedto display life-like behaviors. For example, gaze, gestures, andpositioning of the virtual character should appear natural.

In some embodiments, the virtual character is able to hold the viewer inher gaze. For instance, in accordance with a determination that a lineof sight associated with the wearable head device has changed, thevirtual character may move from a first pose to a second pose. Themovement from the first pose to the second pose may be the virtualcharacter's gaze following the user's line of sight, based on theposition of the wearable head device. Using the methods and featuresdisclosed herein, processing and presenting the movement of the virtualcharacter can be performed with low-latency, allowing the character tolook at the user's eyes directly and accurately.

FIG. 7A illustrates an exemplary mixed reality environment 700,according to embodiments of the disclosure. In some embodiments, thevirtual character 702's gaze and attention may be controlled byinteresting impulses. The movement of the virtual character (e.g.,rotating eyes, rotating neck, rotating body) in response to thecharacter's changing gaze or attention may be presented using themethods presented herein. In some embodiments, the virtual character 702is virtual character 132 or virtual character 500.

Interesting impulses may be generated by sources representing objects,sounds, and people. An interesting impulse has values associated withinterestingness and decay or growth of this interestingness over time,which are dependent on the objects, sounds, and people. Interestingnessof an element (e.g., a real or virtual object, sound, event, person) maybe defined as a likeliness or probability that the element would drawthe attention of the virtual character at a particular time. A firstelement having a higher interestingness value would more likely draw thevirtual character's attention than a second element having a lowerinterestingness value. Interestingness value of an element may vary overtime.

For example, an interestingness value associated with a painting on awall may be higher than an interestingness value associated with a clockon the wall. Impulses can be generated for virtual objects or realobjects detected by sensors of the mixed reality system (optionally witha perception system of the mixed reality system), defined manually, ordefined by external information (e.g., from a database). Objectsdetected by the sensors may be compared with a database of objects andthe detect objects may be matched with objects in the database for anassociated interestingness value and varying interestingness values overtime. In some embodiments, the interestingness values may be dependenton characteristics of the virtual character. For example, if the virtualcharacter is a musician, interestingness values of musical objectsassociated with this virtual character may be higher than thoseassociated with a non-artist virtual character. Based on theinterestingness values of the different identified objects, the virtualcharacter's eye direction, and the virtual character's head turningspeed, the mixed reality system may make a decision on the mostinteresting object at a particular time (e.g., the object that iscurrently occupying the virtual character's attention). In someembodiments, if the most interesting object at a particular time is avirtual object, the virtual character may modify the mixed realityenvironment (e.g., by moving the virtual object) or modify thecharacter's perception of the mixed reality environment (e.g., turningits head and seeing another interesting object) in response.

As an exemplary advantage, the interesting impulse may give the virtualcharacter more life-like qualities by allowing the virtual character toshift its attention between objects and events happening in the mixedreality environment.

For example, virtual character 702 in the mixed reality environment 700has an associated field of view 704 based on the direction of thevirtual character's sight. The direction of the virtual character'ssight may be driven by a base layer of animation, procedural curiosity,or other facts. In this example, interesting objects (e.g., inanimateobject having an interestingness values) may be defined by gaze boxes706A-706G. The gaze box may have a coordinate position and size and maybe associated with objects in the field of view 704. For example, thevirtual character 702 may look between different items on the wall,settling on one for a brief amount of time before looking to a nextitem, analogous to someone waiting in a room. Each gaze box may have aninterestingness value and its value may vary (e.g., decay or grow) overtime. For instance, the interestingness of an active gaze box (e.g., thegaze box the virtual character is currently focused on) may be decayinguntil a threshold value. When the threshold value of interestingness isreached, the virtual character may move its focus on another gaze boxbased on a combination of distance, intersection with the field or view,and stochastic selection, and so on.

The virtual character's gaze and attention may also be determined byinteresting area 708 identified by the mixed reality system or manually.An interesting area 708 may be created in response to detection of asound (e.g., by a sensor of the mixed reality system) associated with anevent such as a door opening, sound of footsteps, or a loud and suddensound. The detected sound may be associated with an event happening in ageneral direction of the sound source. For example, the door in themixed reality environment is opened by the user 710 and generates asound. In response to detection of the sound (e.g., by a sensor of themixed reality system), the virtual character 702 may change its gaze orline of sight towards the general direction of the sound. In someembodiment, upon the detection of an interesting area, the virtualcharacter may shift its focus from a gaze box that was previouslyoccupying the virtual character's attention.

In some embodiments, the virtual character's gaze and attention isdetermined by a social triangle 712. FIG. 7B illustrates an example of asocial triangle that may be associated with a user wearing a wearablehead device. The social triangle 712 may be defined by a width 714 and aheight 716. The social triangle 712 may be associated with an area of ahuman face (e.g., the user of the mixed reality system) that anotherhuman typically focus on during a conversation between the two human.For example, the width 714 is associated with a width of user 710'sface, and the height 716 is associated with a height of the user 710'sface. In some embodiment, more area of the social triangle may be nearthe eyes than the mouth. This area of human face may be detected bysensors of the mixed reality system. Once a social triangle is generatedbased on detection of a human face (e.g., the user of the mixed realitysystem), the gaze and attention of the virtual character may be directedto the detected human face. In some embodiments, upon the generation ofthe social triangle, the virtual character may shift its focus from aninteresting area or a gaze box that was previously occupying the virtualcharacter's attention.

Saccades are be rapid involuntary eye darts that human may make whenlooking at objects or other people. Saccade points, which may not bepresented to the user of the mixed reality system, may be generated forthe virtual character 702 to bound the virtual character's currentsaccade movements. Generating saccades for the virtual characterincreases the believability of the virtual character's human-likefeatures. Saccade points may be generated based on an area of thecurrent most interesting object (e.g., an object that is currentlyoccupying the virtual character's attention), such as a social triangle,an interesting area, or a gaze box, projected onto the eyes of thevirtual character. For example, the range of the virtual character'ssaccade movements may be determined by the boundaries 718A and 718B ofthe eyes of the social triangle projected onto the virtual character'seyes because the virtual character 702 may be focused around the eyeareas of a viewer. Saccade timing and amplitude associated with thevirtual character may additionally correspond to values in nominalphysiological ranges.

Although the gaze box 706, interesting area 708, and social triangle 712are exemplify using specific geometries illustrated in FIGS. 7A-7B, itis understood that the geometrical boundaries illustrated in FIGS. 7A-7Bare not meant to be limiting.

In some embodiments, the virtual character's gaze is controlled by atarget in the mixed reality environment. The target, which may not bepresented to the user in the mixed reality environment, may be movingrelative to the position of the virtual character and the gaze of thevirtual character tracks the movement of the target to generatelife-like eye movements (e.g., small changes in gaze direction). In someembodiments, gaze movement is additionally controlled by ratio ofrotations between the eyes, the neck, and the body to allow the eyes tomove about a natural equilibrium. For example, gaze movements areadjusted for posture discomfort over time; in some instances, the targetmay not be moving while this adjustment is taking place. In someexamples, the virtual character's gaze movements may be based on thevirtual character's current mood or mode. For example, if the virtualcharacter is focused on a task, its gaze movements may not be as greatas a virtual character that is bored.

The virtual character's gaze and body disposition may be dynamicallydetermined by a discomfort system, which allows the character to avoidholding poses for unnaturally long periods of time. In some embodiments,when an animation rig associated with the character is in a first poselonger a character discomfort threshold time, the animation rig wouldmove from the first pose to a second pose (e.g., a more comfortableposition), as described herein. As an exemplary advantage, moving to asecond pose after being in a first pose beyond a character discomfortthreshold time may give the virtual character more life-like qualitiesby allowing the virtual character to shift its position like a humanshifting to a more comfortable position after being in a position for anuncomfortable amount of time.

The mixed reality system may continuously scan the mixed realityenvironment for geometry, so the virtual character appears to stand onwhere the surface (e.g., floor) actually is. In some embodiments, theanimation rig associated with the virtual character is displayed to bepositioned on a surface (e.g., a floor) of the mixed realityenvironment. Sensors of the mixed reality system may sense forcoordinates of the surface of the mixed reality environment, and theanimation rig may be aligned to the surface of the mixed realityenvironment based on the sensed coordinates of the surface. In someembodiments, the animation rig is in a first pose, and the first pose isbased on the alignment of the animation rig and the surface. As anexemplary advantage, aligning the character and the surface of the mixedreality environment gives the user more of a sense that the virtualcharacter and the user exist in a same environment.

FIG. 8 illustrates an exemplary method 800 of a mixed reality system,according to embodiments of the disclosure. The method 800 may beperformed using a mixed reality system, such as mixed reality system112, mixed reality system 200, or wearable system 400. It is understoodthat the steps may be in different orders, some steps may be omitted, oradditional steps may be performed with method 800.

In some embodiments, the method 800 includes displaying (step 802), on adisplay of a wearable head device (e.g., mixed reality system 112, mixedreality system 200, wearable system 400), a view of a character in amixed reality environment. The view of the character may be based on ananimation rig associated with the character. In some embodiments,displaying the view of the character in the mixed reality environmentcomprises rendering the view of the character using Forward+.

In some embodiments, the animation rig comprises primary joints andhelper joints, as described herein. The primary joints may be associatedwith skeletal joints of a character (e.g., virtual character 132,virtual character 500, virtual character 702) associated the animationrig. The helper joints may be associated with locations of the animationrig. The locations may be determined by a helper joint placementcriterion (e.g., manual definition, maximum movement criterion), asdescribed herein. At a first time, the animation rig may be in a firstpose defined by with a first spatial relationships between configurationof the primary joints and the helper joints.

In some embodiments, the method 800 includes determining (step 804), ata second time, that the animation rig is moving from the first pose to asecond pose, wherein the second pose is associated defined by secondspatial relationships between the primary joints and the helper joints.

In some embodiments, determining that the animation rig is moving fromthe first pose to the second pose comprises determining a line of sightassociated with the wearable head device has changed. For example, thegaze of the virtual character toward a viewer has changed, as describedherein.

In some embodiments, determining that the animation rig is moving fromthe first pose to the second pose comprises determining that aninterestingness value associated with a first element of the mixedreality environment exceeds an interestingness value associated with asecond element of the mixed reality environment, as described withrespect to FIG. 7. In some embodiments, the interestingness value isassociated with one of a gaze box associated with an inanimate object ofthe mixed reality environment, an interesting area associated with anevent of the mixed reality environment, and a social triangle associatedwith a user in the mixed reality environment, such as described withrespect to FIGS. 7A-7B.

In some embodiments, the character is displayed to be positioned on thesurface of the mixed reality environment. The method 800 may furthercomprise sensing, with a sensor of the wearable head device, the surfaceof the mixed reality environment and aligning the animation rig and thesurface based on the sensed surface, wherein the first pose isdetermined based on the alignment of the animation rig and the surface.

In some embodiments, the method 800 includes updating (step 806) adisplay, on the display of the wearable head device, of the animationrig from the first pose to the second pose based on movementinformation, wherein the movement information indicates a transformationfrom the first spatial relationships to the second spatialrelationships. In some embodiments, the transformation from the firstspatial relationships to the second spatial relationships is associatedwith the character's muscle movements when the animation rig moves fromthe first pose to the second pose.

In some embodiments, the movement information is represented at least inpart in quaternions, and a loss function associated with the movementinformation comprises combining mean squared error loss of quaternioncomponent values and a penalty for the component values (e.g., equation(1)).

In some embodiments, the method 800 includes transmitting, to a neuralnetwork, as described herein, information associated with a movement ofthe animation rig; and receiving, from the neural network, the movementinformation, wherein the movement information is based on thetransmitted information. The neural network may use an ReLU activationfunction to compute the movement information. In some embodiments, themovement information is computed based on training data, as describedherein, presented to the neural network.

FIG. 9 illustrates an exemplary method 900 of a mixed reality system,according to embodiments of the disclosure. The method 900 may beperformed using a mixed reality system, such as mixed reality system112, mixed reality system 200, or wearable system 400. It is understoodthat the steps may be in different orders, some steps may be omitted, oradditional steps may be performed with method 900. For the sake ofbrevity, examples related to method 900 described with respect to FIGS.7A and 7B are not repeated here.

In some embodiments, the method 900 includes displaying (step 902) aview of a character in a mixed reality environment. The character may bein a first position. For example, the character may have its sight(e.g., looking at, focusing on, paying attention to) on a first element(e.g., an object, a sound, an event, a person) in the mixed realityenvironment, as described with respect to FIGS. 7A-7B. The first elementmay have a first interestingness value at a first time. An object havingan interestingness value may be indicated by a gaze box, a sound or anevent having an interestingness value may be indicated by an interestingarea, and a person having an interestingness value may be indicated by asocial triangle.

In some embodiments, the method 900 includes determining (step 904), ata second time, a second interestingness value associated with a secondelement (e.g., another object, another sound, another event, anotherperson) associated with a mixed reality environment is greater than thefirst interestingness value. For example, the first interestingnessvalue decayed over time and the character may be losing interest of thefirst element. As another example, the character may find anotherelement in the mixed reality environment more interesting at a secondtime.

In some embodiments, the method 900 includes updating (step 906) adisplay of the character to present the character in a second position.For example, the character may have its sight (e.g., looking at,focusing on, paying attention to) on the second element (e.g., the otherobject, the other sound, the other event, the other person) in the mixedreality environment, as described with respect to FIGS. 7A-7B, inaccordance with the determination that the second element has a greaterinterestingness value than the first interestingness value at a secondtime.

Although the disclosed examples have been fully described with referenceto the accompanying drawings, it is to be noted that various changes andmodifications will become apparent to those skilled in the art. Forexample, elements of one or more implementations may be combined,deleted, modified, or supplemented to form further implementations. Suchchanges and modifications are to be understood as being included withinthe scope of the disclosed examples as defined by the appended claims.

What is claimed is:
 1. A method comprising: displaying, on a display ofa wearable head device, a view of a character in a mixed realityenvironment, wherein: the view of the character is based on an animationrig associated with the character; the animation rig comprises primaryjoints and helper joints, the primary joints are associated withskeletal joints of the character, the helper joints are associated withlocations of the animation rig, and at a first time, the animation rigis in a first pose defined by first spatial relationships between theprimary joints and the helper joints; determining, at a second time,that the animation rig is moving from the first pose to a second pose,wherein the second pose is defined by second spatial relationshipsbetween the primary joints and the helper joints; and updating adisplay, on the display of the wearable head device, of the animationrig from the first pose to the second pose based on movementinformation, wherein the movement information indicates a transformationfrom the first spatial relationships to the second spatialrelationships.
 2. The method of claim 1, further comprising:transmitting, to a neural network, information associated with amovement of the animation rig; and receiving, from the neural network,the movement information, wherein the movement information is based onthe transmitted information.
 3. The method of claim 2, wherein theneural network uses an ReLU activation function to compute the movementinformation.
 4. The method of claim 2, wherein the movement informationis computed based on training data presented to the neural network. 5.The method of claim 1, wherein the locations of the helper joints aredetermined by a helper joint placement criterion comprising one or moreof a manual definition and a maximum movement criterion.
 6. The methodof claim 1, wherein the movement information is determined using aregression analysis between the primary joints and the helper joints tocompute the second spatial relationships.
 7. The method of claim 1,wherein determining that the animation rig is moving from the first poseto the second pose comprises determining the animation rig is in thefirst pose longer than a character discomfort threshold time.
 8. Themethod of claim 1, wherein determining that the animation rig is movingfrom the first pose to the second pose comprises determining a line ofsight associated with the wearable head device has changed.
 9. Themethod of claim 1, wherein the character is displayed to be positionedon a surface of the mixed reality environment, the method furthercomprising: sensing, with a sensor of the wearable head device, thesurface of the mixed reality environment; and aligning the animation rigand the surface based on the sensed surface, wherein the first pose isdetermined based on the alignment of the animation rig and the surface.10. The method of claim 1, wherein the transformation from the firstspatial relationships to the second spatial relationships is associatedwith the character's muscle movements when the animation rig moves fromthe first pose to the second pose.
 11. The method of claim 1, wherein:the movement information is represented at least in part in quaternions,and a loss function associated with the movement information comprisescombining mean squared error loss of quaternion component values and apenalty for the component values.
 12. The method of claim 1, whereindisplaying the view of the character in the mixed reality environmentcomprises rendering the view of the character using Forward+.
 13. Themethod of claim 1, wherein determining that the animation rig is movingfrom the first pose to the second pose comprises determining that aninterestingness value associated with a first element of the mixedreality environment exceeds an interestingness value associated with asecond element of the mixed reality environment.
 14. The method of claim13, wherein the first and second elements are each associated with oneof a gaze box associated with an inanimate object of the mixed realityenvironment, an interesting area associated with an event of the mixedreality environment, and a social triangle associated with a user in themixed reality environment.
 15. A system comprising: a wearable headdevice comprising a display; and one or more processors configured toexecute a method comprising: displaying, on the display, a view of acharacter in a mixed reality environment, wherein: the view of thecharacter is based on an animation rig associated with the character;the animation rig comprises primary joints and helper joints, theprimary joints are associated with skeletal joints of the character, thehelper joints are associated with locations of the animation rig, and ata first time, the animation rig is in a first pose defined by firstspatial relationships between the primary joints and the helper joints;determining, at a second time, that the animation rig is moving from thefirst pose to a second pose, wherein the second pose is defined bysecond spatial relationships between the primary joints and the helperjoints; and updating a display, on the display, of the animation rigfrom the first pose to the second pose based on movement information,wherein the movement information indicates a transformation from thefirst spatial relationships to the second spatial relationships.
 16. Thesystem of claim 15, wherein the method further comprises: transmitting,to a neural network, information associated with a movement of theanimation rig; and receiving, from the neural network, the movementinformation, wherein the movement information is based on thetransmitted information.
 17. The system of claim 15, wherein determiningthat the animation rig is moving from the first pose to the second posecomprises determining that an interestingness value associated with afirst element of the mixed reality environment exceeds aninterestingness value associated with a second element of the mixedreality environment.
 18. A non-transitory computer-readable mediumstoring instructions that, when executed by one or more processors,cause the one or more processors to execute a method comprising:displaying, on a display of a wearable head device, a view of acharacter in a mixed reality environment, wherein: the view of thecharacter is based on an animation rig associated with the character;the animation rig comprises primary joints and helper joints, theprimary joints are associated with skeletal joints of the character, thehelper joints are associated with locations of the animation rig, and ata first time, the animation rig is in a first pose defined by firstspatial relationships between the primary joints and the helper joints;determining, at a second time, that the animation rig is moving from thefirst pose to a second pose, wherein the second pose is defined bysecond spatial relationships between the primary joints and the helperjoints; and updating a display, on the display of the wearable headdevice, of the animation rig from the first pose to the second posebased on movement information, wherein the movement informationindicates a transformation from the first spatial relationships to thesecond spatial relationships.
 19. The non-transitory computer-readablemedium of claim 18, wherein the method further comprises: transmitting,to a neural network, information associated with a movement of theanimation rig; and receiving, from the neural network, the movementinformation, wherein the movement information is based on thetransmitted information.
 20. The non-transitory computer-readable mediumof claim 18, wherein determining that the animation rig is moving fromthe first pose to the second pose comprises determining that aninterestingness value associated with a first element of the mixedreality environment exceeds an interestingness value associated with asecond element of the mixed reality environment.